William and Harry are princes of the United Kingdom so it is puzzling why they are so determined to be English instead of British in their identity. The kilt and tartan wearing are only symbols but they have shown very little interest in Scotland.

They have never worn the kilt.

Rejecting the Scottish kilt is only a symbol.

The lack of interest in Scotland does not help keep the Kingdom United.

William & Harry have spent a fair majority of there childhood life in Scotland. They were both there when their mother died. William spent 3 years at St Andrews at University.

What else are they supposed to do?
They do very little royal duties in England or anywhere else in the UK, neither has a scottish title like their father does. How are they supposed to openly show you there are acknowledging their scottish identity?

They are officially Princes of Wales, IMO they should concentrate on that first then move onto engagements elsewhere.

They openly support England at football and rugby matches against Scotland and Wales and all the other nations over which their grandmother is Queen and their father will be King.

It is blatantly obvious that they see themselves as English first and maybe British second - like most British people actually - identifying more with their English, Welsh, Scottish or Irish background first and foremost over their British one.

Since become adults they have spent very little time in Scotland, except for William's years at uni there (interestingly none of the Queen's grandchildren have opted for the Oxbridge unis but have gone to the lesser known ones on a world stage - although St Andrews is also a very old one).

All members of the British Royal Family since 1603 have been raised in England. From the time of Victoria to Elizabeth II, there has always been an important recognition of the distinctive Scottish element in their British identity - they all spent time in Balmoral and princes all wore kilts. Now this tradition has ended with the grandchildren of Elizabeth. This indicates a troubling rejection of part of their Britishness. Troubling because it gives weight to separatism and to the break up of the United Kingdom. If the Scottish people think the Windsors are purely English with no interest in Scotland, they will become republicans very quickly I would expect.

Perhaps a new title is needed for the second son or daughter of the monarch: Prince/Princess of Scotland? Didn't the throne attempted to win the favor of the Welsh by creating the Prince of Wales?

However the eldest son already has a number of titles that a specifically reserved for the use of the eldest son of the monarch and heir to the Scottish throne (and like Cornwall for the English throne) pre-date the merging of the crowns.

William and Harry have all spend considerable time in Scotland whilst growing up, and continue to do so in their time off from their military duties. I agree they have not been pictured in kilts, but I am sure that is just a question of time.

Grandchildren of the Queen are not wearing kilts. This was a costume invented by George IV in 1822 to show Scotland that it is part of the United Kingdom and that the monarchy has a special affection for this part of the realm. The children of Queen Elizabeth's sons and daughters have shown little if any affinity with Scotland. William went to university there - like many other upper class English boys who could not get into Oxford and Cambridge. There is no evidence of a lasting link. Only The Queen, Philip and Charles retain the relationship.

The Queen's male grandchildren have all been photographed in kilts, just not as yet as adults.
It's false to say that the children of Queen Elizabeth's sons and daughter have shown little if any affinity with Scotland. Peter Philips (the Queen's first grandchild) played schoolboy rugby for Scotland, he was a good enough rugby player to be chosen for schoolboys international rugby tournaments, his rugby career came to an end when he damaged his knee.
Both Peter and his sister Zara were educated in Scotland, they attended Gordonstoun. Peter has attended both Western Isles cruises that the Queen has organised in the past few years.
William chose to attend an university in Scotland, even if he had intended to go to Oxbridge and didn't get in, (there is no evidence he ever even applied) there are other English universities who are just as prestigious as St Andrews eg Bristol (Where one of the Blair sons went after he wasn't accepted by Oxford) William said he deliberately chose St Andrews as he wanted to spend some time living in Scotland, he said in the future he would probably spend quite a bit of time in Wales (future Prince of Wales reference) his university years were time for him to get to know Scotland well. He spent 4 years at St Andrews and holidays regularily at Balmoral, usually Birkhall. Harry spends less time at Balmoral, he prefers to holiday in the sun.
Beatrice and Eugenie go to Balmoral each year, at times with just their father and other times when the Queen is in residence. They attended both Western Isle cruises as well.
Finally the 2 youngest grandchildren Louise and James don't get a choice, their parents spend August at Balmoral and they do too!

Just wearing a kilt doesn't mean you're Scottish, anyone can wear a kilt and not have any connection at all with Scotland! Do you expect all German men to wear Ledderhosen?

As far as supporting the Scottish rugby team, Princess Anne is the patron and she attends all the matches at Murrayfield. The royals don't double up, William is vice patron of the Welsh rugby side (the Queen in patron), Harry has just been asked to be patron of the English side.

English? The British royal family have never been particularly English or Scots. Victoria and Albert did delude themselves somewhat with their wee heeland haem, but royalty these days, like cafe society, is more international than national.

Royalty provides visual symbolism to unify the nation. William needs to wear a kilt to demonstrate that he will be king of the UNITED kingdom. Loden and Tracht are also acceptable as Saxe Coburg Gothas.